If you recently bought tomato plants, especially from the "big box" stores - be on the look out! I just heard on the Cornell Cooperative Extension podcast this morning that a report went out Friday about late blight being discovered in a bunch of tomato plants provided by a big grower in Texas (the article at the link below says Alabama), but provided to stores here in the NE. What they were saying in the podcast was there were reports from Ohio to Maine of late blight signs on tomatoes. This is the same disease that caused the Irish potato famine. Part of the concern is that someone might buy infected tomatoes, figure the plant's died off and just leave it in place, but the spores will spread to neighboring plants, the neighbor's plants, plants across town, and on to farms and commercial growers. I guess it's highly infectious.
Here's more info:
I figure most folks reading this will already have established plants, and probably ones they started from seed. But that doesn't mean it might not spread to your plants from a neighbor... You might wanna pass the word on to anyone you know who grows tomatoes, potatoes, eggplants and petunias (I'm not sure what else it can affect).